Having trouble with recovering Destro resources after combat?

I am having some trouble recovering my Embers when i am out of combat during leveling.
In other words, when i am at 0 Embers i find it hard to get them to at least 2 or 3 on the mobs while leveling.

When i am around 3 embers, i can usually keep spending them and creating them with the Chaosbolt/Shadowburn.
But if i lose all embers (zero) i really can not get any back up unless i spam Incinerate to death on at least 2 or 3 mobs - that is like 10 incinerates per mob, and at least 3 mobs for 2 embers, so a lot of time wasted just spamming Incinerate to generate embers.

Is there anything i am missing that warlocks can use to regain Embers quickly or when starting combat with zero Embers?

While Grubjuice is correct, he leaves out the "why" in his explanation.

An unlisted feature of Shadowburn is that in addition to refunding the Ember if the target dies within 5 seconds, it also generates an Ember if it gets the killing blow on a target. In other words, if you kill the target with a single Shadowburn you get two Embers back. This creates the awesome Destro leveling engine.

Chaos Bolt your target as an opener (if you have two or more Embers), use a Conflag or two to get them into execute range, Shadowburn, move on to the next mob and repeat. When possible pull with Havok and aim your Chaos Bolt at a second target while your Voidwalker keeps the first one busy. At Mists levels you'll want to open with a Conflag, once your Backdraft works on Chaos Bolt.

Follow those easy steps, and you'll never complain about how long quest mobs are taking to die again.

All specs could benefit from a long cooldown ability that instantly grants them half their secondary resource.Conniption
5 minute cd: Instantly grants the caster 2 Soul Shards, or 500 Demonic Fury, or 2 Burning Embers, depending on her specialization.

That would be good, but i would rather have a % Health Cost and a slightly lower cooldown